The car company with the herringbone gear shape as the company logo is the Citroen company logo. Citroen's logo is double-shaped, indicating that they invented the herringbone gear. Citroen's century-old logo originated from the herringbone gear invented by brand founder Andre Citroen in 1900. Compared with the traditional single helical tooth, this herringbone helical tooth can effectively reduce the lateral force generated by the helical tooth on the gear shaft while retaining the bite force and stability of the traditional helical tooth, thus improving the durability of the parts. 19 12, Mr. Andre Citroen founded his own gear company and began to use double fonts as the company trademark. Later, when Citroen was founded, it also continued the double-character trademark.